The present invention relates to apparatuses and methods for coffee-making machines and, more particularly to coffee-making machines that have water level measurement devices using load cells.
Coffee-making machines, a term which is understood to include within it espresso-making machines, require heating water used for making the coffee or espresso. The water used for making espresso or coffee is not filtered water, which would not be suitable for drinking. Accordingly, the water used for making the coffee or espresso is water in which there are a significant amount of dissolved minerals. This may be tap water or it may be bottled water containing minerals.
It is well known that heating water causes at least some of the minerals to precipitate out of solution either through evaporation of the water solvent due to the heat or through precipitation of the solute out of solution as fine particles. In either case, the particles that come out of solution gravitate to the bottom or side of the container holding the solution as sediment. For example, calcium deposits are a common outcome of heating water.
An important component of the coffee making machine is the water level measuring instrument. In the prior art, these are internal gauges that indicates whether the water has reached the fill line—i.e. whether the water tank is full or needs to be filled. In one version seen in FIG. 1, a float 6 extends downward into the water tank 3 having a fluid entrance 1 and a fluid outlet 2. When the level of the water 4 rises to reach the level of the float 6, which extends down to the fill line, the float is impacted by the water which causes the float 6 to go up and activate a tiny magnetic switch 7, sending a YES signal to a controller 9. Otherwise, in other conditions, the switch remains inactivated and a NO signal is being transmitted to the controller. When water in the water tank is heated the calcium and other minerals precipitate and evaporate out of solution and cause scaly calcium and lime to build up on the float.
In a second type of water level measuring device seen in FIG. 2, an elongated and thin metal probe 8 extends downward into the water tank. When the water level rises to touch the probe, which extends to the fill line, the probe sends a YES signal to the controller. Otherwise, a NO signal is transmitted to the controller.
In both cases, the water level measurement device, or at least part of it, is quickly exposed to the calcium and lime deposits that precipitate or evaporate out of the heated water.
It is well known that calcification and the deposit of lime sediments are a continuing problem for wet water level measurement components and other wet components of coffee-making machines for several reasons. The calcium and lime sticks to everything that touches water. This includes the water level measurement device and other sensors and other critical components. The build-up of scale interferes with the functioning of the water level measuring components and causes it to generate wrong readings that either overstate the water level or understate the water level. In addition, the float gets stuck.
If the water level measuring device gives a false reading that the water level is lower than it actually is, which is what usually happens from scale build up, the real water level will be too high and this causes the tank to keep filling up eventually resulting in overflowing. The water floods the entire machine. It is not uncommon for the malfunctioning water level measuring device to cause such overflowing that the entire premises of the business are flooded. Flooding water might contact electricity and cause a short circuit, shutting down the whole machine and possibly even other machines or appliances connected to the same electricity line or affected by flooding water. Damage can be very expensive to repair and even irreversible.
In addition, if the water level measuring device were to give a false reading that the water level is higher than it actually is, the actual water level will be too low and this will cause overheating, which also damages the coffee making machine, or other machine of the food industry.
As a result of the build-up of scaly deposits on the components of coffee making machines, machines that are supposed to last 10 to 20 years end up lasting 2 to 4 years. Accordingly, equipment replacement costs are astronomical. Labor costs for maintaining these coffee making machines are also high since a certified espresso machine technician is required in order to replace these heating elements. Their work takes several hours and the machine is down during that time, affecting business.
One thing that can be done to try to prevent build-up of lime and calcium on the heating element is to increase the frequency of maintenance checks. Chemicals for cleaning the lime and calcium also cost money. Consequently, increasing the frequency of maintenance checks increases labor costs and generates a significant increase in overall maintenance costs.
Prior attempts to solve the problem of the scale deposits include the use of water softeners that are placed into the water. Water softeners exchange calcium and magnesium ions with twice as many sodium ions. This ion exchange is expensive to maintain, requires a lot of sale to operate and can require a lot of extra water. Environmentalists maintain that water softeners pollute our environment and harm people on salt restricted diets. This has to legislation—at the state or local level—in approximately 34 states of the United States restricting the use of water softeners in sanitary sewage systems. Water softeners may also speed up pipe damage as the more salty water flows through the piping. Approximately two years from now additional legislation is expected to be implemented further restricting use of water softeners.
An additional prior art attempt to solve the problem involves the use of filters in the coffee-making machines. Filters are expensive. In addition, the filters must be maintained properly, however, in order to be effective. In fact, the filters need to be replaced weekly. Applicant's experience in servicing coffee making machines over decades is that filters are simply not maintained properly. They are not replaced when they should be. A common reason, besides laziness, is that there is a frequent labor changeover in the retail outlets that use coffee-making machines and there is a constant shortage of trained personnel able to change the filters.
Another type of water level measuring device is ultrasonic. Although it does not touch water it costs approximately $700, which is much too expensive to be practical to be used to measure the water level in a coffee making machine or other food industry equipment. It is used in large industrial applications such as large scale weight machines, including truck weigh stations.
Applicant has also heard of a company on the Internet calling itself “Scalebusters” that offers a computerized system installed on the incoming water line of a facility. The computer system uses an oscillating electronic field that claims to change the physical size, shape and charge of calcium molecules. Although alleged to be less expensive than water softeners, this computer system is expensive to install and maintain.
There is a compelling need to have a method and apparatus for solving the build-up of lime and calcium deposits from water that affects the water level measuring components and other critical components of coffee-making machines.